ListenerModifier class

A widget that calls callbacks in response to common pointer events.

It listens to events that can construct gestures, such as when the pointer is pressed, moved, then released or canceled.

It does not listen to events that are exclusive to mouse, such as when the mouse enters, exits or hovers a region without pressing any buttons. For these events, use MouseRegion.

Rather than listening for raw pointer events, consider listening for higher-level gestures using GestureDetector.

Layout behavior

See BoxConstraints for an introduction to box layout models.

If it has a child, this widget defers to the child for sizing behavior. If it does not have a child, it grows to fit the parent instead.

{@tool dartpad} This example makes a Container react to being touched, showing a count of the number of pointer downs and ups.

** See code in examples/api/lib/widgets/basic/listener.0.dart ** {@end-tool}

Inheritance
Available extensions

Constructors

ListenerModifier({Key? key, Key? modifierKey, Widget? child, PointerDownEventListener? onPointerDown, PointerMoveEventListener? onPointerMove, PointerUpEventListener? onPointerUp, PointerHoverEventListener? onPointerHover, PointerCancelEventListener? onPointerCancel, PointerSignalEventListener? onPointerSignal, PointerPanZoomEndEventListener? onPointerPanZoomEnd, PointerPanZoomStartEventListener? onPointerPanZoomStart, PointerPanZoomUpdateEventListener? onPointerPanZoomUpdate, HitTestBehavior behavior = HitTestBehavior.deferToChild})
Creates a widget that forwards point events to callbacks.
const

Properties

behavior → HitTestBehavior
How to behave during hit testing.
final
hashCode → int
The hash code for this object.
no setterinherited
key → Key?
Controls how one widget replaces another widget in the tree.
finalinherited
modifierKey → Key?
The actual key of the widget, which Modifier wrapped
finalinherited
onPointerCancel → PointerCancelEventListener?
Called when the input from a pointer that triggered an onPointerDown is no longer directed towards this receiver.
final
onPointerDown → PointerDownEventListener?
Called when a pointer comes into contact with the screen (for touch pointers), or has its button pressed (for mouse pointers) at this widget's location.
final
onPointerHover → PointerHoverEventListener?
Called when a pointer that has not triggered an onPointerDown changes position.
final
onPointerMove → PointerMoveEventListener?
Called when a pointer that triggered an onPointerDown changes position.
final
onPointerPanZoomEnd → PointerPanZoomEndEventListener?
Called when a pan/zoom finishes.
final
onPointerPanZoomStart → PointerPanZoomStartEventListener?
Called when a pan/zoom begins such as from a trackpad gesture.
final
onPointerPanZoomUpdate → PointerPanZoomUpdateEventListener?
Called when a pan/zoom is updated.
final
onPointerSignal → PointerSignalEventListener?
Called when a pointer signal occurs over this object.
final
onPointerUp → PointerUpEventListener?
Called when a pointer that triggered an onPointerDown is no longer in contact with the screen.
final
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited

Methods

build(BuildContext context) → Widget
Describes the part of the user interface represented by this widget.
inherited
buildWithChild(BuildContext context, Widget? child) → Widget
A build method that receives an extra child parameter.
override
createElement() → SingleChildStatelessElement
Create a SingleChildStatelessElement
inherited
debugDescribeChildren() → List<DiagnosticsNode>
Returns a list of DiagnosticsNode objects describing this node's children.
inherited
debugFillProperties(DiagnosticPropertiesBuilder properties) → void
Add additional properties associated with the node.
inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
toDiagnosticsNode({String? name, DiagnosticsTreeStyle? style}) → DiagnosticsNode
Returns a debug representation of the object that is used by debugging tools and by DiagnosticsNode.toStringDeep.
inherited
toString({DiagnosticLevel minLevel = DiagnosticLevel.info}) → String
A string representation of this object.
inherited
toStringDeep({String prefixLineOne = '', String? prefixOtherLines, DiagnosticLevel minLevel = DiagnosticLevel.debug}) → String
Returns a string representation of this node and its descendants.
inherited
toStringShallow({String joiner = ', ', DiagnosticLevel minLevel = DiagnosticLevel.debug}) → String
Returns a one-line detailed description of the object.
inherited
toStringShort() → String
A short, textual description of this widget.
inherited

Operators

operator ==(Object other) → bool
The equality operator.
inherited